Re: [PATCH v2] common/defrag: skip defrag tests on DAX-enabled filesystems

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Jun 04, 2026 at 05:53:05PM +0530, Disha Goel wrote:
> Online defragmentation is not supported on ext4 DAX-enabled filesystems.
> The ext4 defrag ioctl (EXT4_IOC_MOVE_EXT) returns EOPNOTSUPP when used
> on DAX files.
> 
> Add an ext4-specific check in _require_defrag() to skip tests when DAX
> is enabled, avoiding false failures on ext4/301-304, ext4/308, and
> generic/018.
> 
> XFS defrag works with DAX, so this check is ext4-specific.
> 
> Signed-off-by: Disha Goel <disgoel@linux.ibm.com>
> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
> ---
> Changes in v2:
> - Made the check ext4-specific as XFS defrag works with DAX
>   (feedback from Darrick)
> - Use __scratch_uses_fsdax() instead of grepping MOUNT_OPTIONS
> - Removed unnecessary comment as _notrun message is self-explanatory
> 
>  common/defrag | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/common/defrag b/common/defrag
> index 055d0d0e..f17271cd 100644
> --- a/common/defrag
> +++ b/common/defrag
> @@ -6,6 +6,10 @@
>  
>  _require_defrag()
>  {
> +    if [ "$FSTYP" = "ext4" ] && __scratch_uses_fsdax; then

Shouldn't this be:

	ext4)
		__scratch_uses_fsdax && _notrun "..."
		;;

in the case statement below?

--D

> +        _notrun "ext4 online defrag not supported with DAX"
> +    fi
> +
>      case "$FSTYP" in
>      xfs)
>          # xfs_fsr does preallocates, require "falloc"
> -- 
> 2.45.1
>